my girlfriend has a black oranda and today we noticed that there is a white patch in the center of his wen. here are her readings, ammonia 1.0, nitrite .24 nitrate is 5, ph is 7.6, it is a 10 gal with topfin 20 filter, it is not acting strange and we changed the water today.

How is the fish acting?
Those are some pretty bad levels for the ammonia. I would do an immediate water change again and try to get them down.

As far as the white on the wen, it can often be just growth or a parasite or even fungus. It is better if we can have more info from above.
I am also going to move this to the diagnosis forum and not 911 unless you tell me the fish is dying and needs immediate attention.
Post back soon.

could it be bump marks? do you have any sharp objects in your tank?

How long has your tank been running? It sounds to me as though it hasn't fully cycled yet. I would probably do mini water changes daily to help ease the stress on your goldie with the high ammonia levels.
I would also do a salt treatment, 1 teaspoon per gallon of water or 1 tablespoon per 5 gallons of water. The salt will help treat your goldfish if he does have a fungus and also help reduce the stress from the nitrite level. Just remember to dissolve the salt in tank water before you add it to the tank.
Hope this helps!

Does it look like this?

If so it's wen growth and there is nothing wrong... My oranda get's it about twice a year. Almost looks like either a white bruise or sometimes whiteheads. But not to get these mixed up with Breeding stars which are also apparent in the picture.

Let me know....